Examples of deposits on oven wall surfaces that affect lives of oven bodies of industrial ovens include carbon adhered on an oven wall surface of a coke oven. In a coke oven, operations of carbonizing coal introduced into the oven for a certain period of time and discharging the formed red-hot coke outside the coke oven by a coke extruding apparatus are repeated. When such operations are performed, carbon deposits on the oven wall surface of the coke oven and grows unevenly. If this growth proceeds, parts of the deposited carbon may be peeled off and fall in the oven.
Moreover, firebricks forming the oven wall surface are subjected to mechanical or thermal impacts upon the introduction of coal or gradually eroded by, for example, parts of the firebricks being peeled off along with the carbon grown on the wall surface. As a result, the oven wall surface of the coke oven becomes irregular, causing clogging in the oven during the coke extrusion operation. Clogging in the oven not only reduces operational efficiency of the coke oven but also places heavy load on the oven body, and even shortens the life of the oven body. In particular, if the carbon adhered to and grown on the oven wall surface is peeled off, level differences due to the irregularity formed on the oven wall surface often increase and therefore, the clogging in the oven becomes easier to occur upon the coke extrusion. Accordingly, it is very important for operating a coke oven to maintain smoothness of a wall surface in the coke oven.
However, in the operations presently performed, irregularity formed on oven wall surfaces in coke ovens is inevitable. Therefore, in order to prolong the life of an oven body as much as possible, it is necessary to ascertain the irregularity formed on the oven wall surface and appropriately perform repair to efficiently smooth out the irregularity.
As an oven wall shape measuring apparatus therefor, for example, a technique of capturing an oven wall surface images with a linear image camera and measuring irregular shapes using spot-like laser light is known (see Patent Literature 1). Moreover, a technique of performing, with a same imaging device, measurement of irregular shapes by irradiating slit-like laser light to an oven wall surface and imaging self-emitting light from the oven wall surface (e.g., light in the red spectrum region emitted from the red-hot oven wall surface) is also known (see Patent Literature 2).